1. Field of the Invention
The present invention relates to gas sensing systems, and in particular, to an optical system for identifying, characterizing and/or determining the concentration of various gases in a gas mixture or sample that employs Raman scattering.
2. Description of the Related Art
The detection and characterization of molecular gases in a given sample is a relatively difficult challenge. Usually, this task is relegated to expensive and time consuming processes like mass spectrometry and gas chromatography. Furthermore, numerous industrial applications require such gas-phase analysis for pollution and process control. For example, in large natural gas-fired turbine electricity generators, large quantities of natural gas are mixed with air and burned. Because natural gas comes from a variety of sources, the composition of the gas changes often. If the composition of natural gas were known a-priori, turbine efficiency could be improved by adjusting the fuel/air mixture and other operating parameters. This control capability requires measurement of the components of the natural gas to better-than 0.1% accuracy, with the measurement being performed at least once every second. There is currently no commercially available sensor or sensing system that is able to measure all of the natural-gas components in one second.
There is thus a need for a sensor and/or sensing system that is able to quickly and reliably identify, characterize and/or determine the concentration of various gases in a gas mixture or sample, such as, without limitation, natural gas burned in a natural gas-fired turbine electricity generator.